Calcium antagonists, a new class of antihypertensive agents.

The mechanism of action of Ca++ antagonists remains debatable. Not all voltage-sensitive calcium channels have the same sensitivity to organic calcium blockers. Those in smooth muscle are clearly more sensitive than those in heart, and at least some of those in brain are not blocked at all. It is possible that in vascular smooth muscle, calcium antagonists act essentially on receptor-operated channels. In any case, calcium antagonists are potent antihypertensive agents, but in clinical practice they have limitations. A second generation of dihydropyridines may provide a higher degree of therapeutic selectivity.